The effects of sewage effluent on macroalgal and seagrass abundance, dry weight and diversity within Grahams Harbor, San Salvador, Bahamas

by Holman, Krista Elaine

Abstract (Summary)

The algal and seagrass abundance, dry weight and diversity were surveyed at a site along the coast of Grahams Harbor in San Salvador, Bahamas in the Caribbean during June 2004. One hundred randomly distributed plots were surveyed via SCUBA to determine the influence of a sewage effluent pipe on algae and seagrass assemblages. The objectives of the study were to determine if there was a distinction among regions of marine algae and seagrasses due to the effluent, and if distance from the effluent source influenced diversity (measured through Shannon’s Diversity Index, H', Simpson’s Diversity Index, D' and Evenness, E'), species richness, percent cover and dry weight. Results showed that the dry weight and percent cover decreased significantly with a decrease in distance from the pipe. Additionally, regions outside the flow of the effluent pipe showed significant increases in species number.